Title

Author

Degree

Doctor of Philosophy

Program

Psychology

Supervisor

Dr. Leora Swartzman

Abstract

Purpose: Patients’ decisions about whether or not to adhere to their prescribed regimens are shaped not only by their knowledge and beliefs about their condition and its treatment options, but also by what they value in these domains. This study represents an integration of theory and methods from nursing/public health, psychology and economics to explore the additive effects of knowledge, beliefs and preferences on adherence to preventer medication in a sample of patients with asthma. It was hypothesized that knowledge, beliefs and preferences pertaining to long term outcomes would independently predict improved adherence. Method: 140 patients with asthma were asked to complete a series of surveys assessing their knowledge and beliefs about asthma and its treatments as well as a discrete-choice task (DCE) in which they selected which hypothetical medication they would choose from among eight choice sets that varied along seven attributes (Long Term Efficacy, Short Term Efficacy, Immediate Relief, Number of Inhalers, Steroid Dose, Administration Time, and Side Effects). Adherence was measured using the self-report Medication Adherence Report Scale one month after their clinic visit. Results: A latent cluster analysis of the DCE data suggested four distinct groups of patients, namely, those whose choices were guided by (1) long term benefits, (2) medication side effects, (3) the trade-off between side effects and efficacy and (4) all attributes equally. Multiple regression analyses indicated that pathophysiology knowledge, the belief that preventer medication is necessary and membership in the group valuing long term outcomes each uniquely predicted reported adherence, together explaining 39% of the variance. Preferences for long term outcomes predicted an additional 10% of the variance above and beyond that accounted for knowledge about asthma pathophysiology and treatment beliefs alone. Conclusion: These findings suggest that to improve patient adherence to asthma preventer medications, patients should be helped to understand why they require medications. Once the long term effects of asthma are understood, believed and valued, patients will be more likely to adhere. Via DCE methodology, we have also demonstrated a novel approach to elucidating patient variations in treatment-related values.